Safety stop



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A. F. CASE SAFETY STOP Filed April 3, 1925 Oct. 1, 1929.

Oct. 1, 1929.

A. F. CASE 1,730,188

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0a. 1, 1929. A. F. CASE 1,730,188

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A. F. CASE Oct. 1 1929.

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SAFETY STOP Filed April 1925 6 Sheets-Sheet 6 I is-.8.

ave nhya Patented. Oct. 1, 1929 UNITED STATES PATENT OFFICE ARTHUR 1:. CASE, OF CLEVELAND, OHIO, ASSIGNOR TO THE WELLMAN SEAVER MOR- GAN COMPANY, OF CLEVELAND,

OHIO, A CORPORATION OF OHIO SAFETY STOP Application filed April 3, 1925. Serial No. 20,408.

This invention relates to safety stops for structures adapted to travel along a trackway. and has particular reference to a safety stop for material conveying bridges, to hold the structure against movement by wind pressure on it, the present invcntion being, an improvement in safety stops of the type disclosed and claimed in my co-pending applications Serial No. 554 080, filed April 17, 1922. and Serial No. 735,162, filed April 30, 192% ,The present invention has for its object to provide an actuating device for the wheel blocking members in which the actuating mechanism is protected against undue strain in the event that a wheel blocking member should be held to the rail by a wheel of the bridge, and further to provide actuating means which in the event that the blocking number is held beneath the wheelwill act to automatically shift the blocking member to inoperative position as soon as the wedge is released by a movement of the bridge.

A further object is to provide an actuating mechanism for a plurality of blocking members by which all of the blocking members which are free from the wheels may be simultaneously moved to releasing position, and those held upon the rail by wheels of the bridge may be automatically shifted out of wheel engaging position as soon as the bridge has been moved to free them from the wheels.

A further object is to provide means for more securely holding the blocking member against sliding movement along a rail.

further object is to provide indicating devices associated with the blocking members which will show the operatorwhich way the bridge should be shifted to release any blocking members held beneath the wheels. With the above and other objects in view the invention may be said to comprise the device as illustrated in the accompanying drawings hereinafter described and particularly set forth in the appended claims, together with such variations and modifications thereof as will be apparent to one skilled in the art to which the invention appertains.

Reference should be had to the accompanying drawings forming a part of this specification, in which F ig'. 1 is a Side elevation showing the low'er portion of a traveling bridge having oppositely disposed wheel blocking members associated with wheels of the front and rear trucks; Fig. 2 is a side elevation of one of the wheel blocking members and the connection for actuating the rail clamp and for shifting the member out of wheel engaging position showing in dotted lines the position of the counterweight and actuating connections at the point in their movement where the clamping jaws have been moved to open position and the bodily movement of the blocking member begins; Fig. 3. is a section on line 33 of Fig. 2; Fig 4 is a to plan view of the operating mechanism on t e frame of the bridge; Fig. 5 is a side elevation of the mechanism shown in Fig. 4; Fig. 6 is a section on line 6-6 of Fig. 4; Fig. 7 is a section on line 77 of Fig. 4; and Fig. 8 is a wiring diagram showing the motor and clutch controlling circuit and one of the signal circuits associated with the blocking members.

Referring to the accompanying drawings. the sill of the bridge which extends longitudinally of: the supporting rails upon which the operating mechanism is mounted is designated by the reference numeral 1, and the supporting wheeels which are carried by suitable trucks spaced longitudinally of the sill are indicated by the reference numeral 2.

As shown in Fig. 1 of the drawing a wheel blocking member is associated with the rear wheels of trucks at the front and rear ends of the sill, the forward wheel blocking members being in front of the wheels with which they co-operate. and the rear blocking members being at the rear of the Wheels with which they cooperate in order to prevent movement of the bridge in either direction.

The wheel blocking units are all identical in construction. and each has a body portion 3, Fig. 2 in the form of a casting which is adapted to rest upon the top surface of the track rail. Extending forwardly from the body portion 3 there is a wedge-shaped portion 4 the bottom of which rests upon the rail and the top of which has a curvature corresponding substantially to the curvature of the wheel with which it cooperates.

The body portion 3 of the wheel'blocking member carries clamping jaws 5 which engage opposite sides of the ball of the rail upon which the blocking member rests to lock the blocking member against sliding movement along the rail, and in order to obtain a more efficient holding action the clamping jaws 5 are mounted adjacent the rear end of the body 3. The jaws 5 are carried by pivot pins 5* adjacent the loweredge of the body 3, the pins 5 being horizontal and extending lengthwise of the body. The jaws 5 have upwardly extending arms 6 which-are connected by inwardly extending toggle links 7 with an actuating lever 8 which is pivoted at 9 to the upper portion of the body 3 forwardly of the point of connection of the link 7 thereto. The lever 8 extends rearwardly beyond the point of connection of the link 7 and upon its rear end carries a counterweight 10. The links 7 are so arranged that when the rear end of the lever 8 is moved downwardly by the counterweight the upper ends of the arm 6 are spread apart, and the jaws 5 are moved into clamping engagementwith the rail. The lever 8 projects forwardly beyond the pivot 9, and, connected to the forward end of the lever, there is an extensible link 11 which forms a connection between the forward end of the lever and the sill 1, the link 11 having a slot 12 at its upper end which receives a pin 13 secured to the sill 1.

The counterweight 10 is connected by a pair of links 14 with arms 15 integral with an operating lever 16 which is pivoted at one end on a shaft 17 carried by the sill 1,. and has its opposite end 18 curved upwardly, the arms 15 being between the pivot 17 andthe upwardly curved portion 18 of the lever 16.

The upwardly extending end; portion 18 of the lever 16'has pivotally connected thereto a spring cage which is formed of two telescopically connected parts, one of the parts of the cage having a rear plate 19 connected by a pivot pin 20 to the upturned portion 18 of the lever and an opposite end plate 21 connected to the plate 19 by bolts 22. The other part of the spring cage has an end plate 23 slidably mounted upon the bolts 22 and connected by means of bolts 24, which extend through and are slidable in the plate 21, with an end plate 25 outside the end plate 21 of the other part of the cage. A compression coil spring 26 is mounted within the rods 22 and 24 and bears at one end against the plate 23 and at the opposite end against the plate 21. The end plate 25 has connected thereto a pull rod 27 which is connected at its opposite end to a bell crank 28 which is in turn connected by a connecting rod 29 to one of the crank arms 30 on an operating shaft 31 adjacent the center of the sill.

Means is provided for turning the shaft 31 through an angle suflicient to shift the lever 16 far enough to release the clamps and swing the blocking members out of wheel engaging position. The spring 26 .is relatively stiff and is compressed but sli htly in the normal operation of the device. utficient play, however, is provided between the plates 21 and 23 of the spring cage to permit the shaft 31 to be turned through the entire angle necessary under ordinary circumstances to disengage the blocking members regardless of whether a blocking member is shifted or not. It sometimes happens that a wheel will ride up on a wedge member 4 and the weight resting upon the wedge member will prevent the movement of the blocking member to inoperative position. In such cases the operation of the shaft 31 causes-the lever 16 to be turned about its pivot until the counterweight 10 has been raised sufficiently to release the clamping jaws and to swing the link 11 down until the upper end of the slot 12 engages the pin 13. Further pull on the lever 16 will tend to swing the blocking member bodily about the pin 13 as a pivot into a position clear of the rail with the wedge 4 spaced from the wheel and rail far enough so that it will not interfere with the travel of the bridge. The link 11 will be adjusted to a length such that immediately after the lever 8 has been moved to the position to release the clamps, as shown in dotted lines in Fig. 2, the fulcrum of the lever 8 will be shifted to the pivotal connection thereof with the link 11 so that further upward movement of the link 14 will swing the link 11 rearwardly and with it the blocking member which, as the lower end of the link 11-is raised by its rearward movement about the pin 13 as an axis, moves rearwardly and upwardly from the position shown in Fig. 2 to a position in which its bottom edge is clear of the rail and its forward end is clear of the wheel; If, however, a wheel should be resting upon the wedge portion of a clamping member the pull on the rod 27 instead of imparting further movement of the lever 16 will compress the spring 26. As will be more fully explained hereinafter, means is provided in connection with the operating shaft 31 for locking the shaft in a position for holding the blocking members out of engagement with the whecl and rail. If the shaft 31 be turned to this position and locked the springs 26 associated with any blocking members which are held to the rail by a. wheel will be under sufficient compression to automatically shift such blocking members to inoperative position as soon as the blocking members are released from the wheels. The blocking members so held may be released by shifting the bridge in the proper direction to cause the wheels to roll ofi' of the wedges upon which they are resting. It should be noted that the connection between the blocking members and the sill provided by links 11 and 14 permit some relative movement between the bridge and the clamping members when the clamping members are in engagement with the rail, so that the wheels at one end of the sill may in some instances be forced up onto the blocking wedges.

The operating and controlling mechanism for. the shaft 31 is mounted upon a platform 32 substantially midway between the ends of the sill 1, and upon the platform 32 there is mounted an electric motor 33 which has a shaft 34 extending into a reduction gear case 35 in which there is a suitable reduction gearing for driving a transverse counter-shaft 36 from the shaft 34. Loosely mounted on the shaft 36 is a pinion 37 to which is fixed one part of a magnetic clutch 38 by which the pinion 37 may be locked to the shaft 36. The pinion 37 meshes with a large gear 39 on the operating shaft 31 so that the shaft 31 may be driven from the motor when the clutch 33 is engaged. The motor 33 is a one-direction motor, and means is provided for preventing reverse rotation of the shaft 36. To this end the shaft 36 has fixed thereto a ratchet 40 which is engaged by a spring-pressed pawl 41 which permits rotation of the ratchet in one direction only.

The motor 33 drives the shaft 31 in a direction to shift the wheel blocking members to inoperative position and the shaft 31 is released when the clutch 38 is disengaged to permit the blocking members to move by gravity to wheel engaging position. The shaft 31 has fixed thereto an arm 42 which engages with a limit switch arm 43 mounted on the platform 32 and controlling a switch in the motor circuit. The arm 42 serves to actuate the switch to stop the motor when the shaft 31 has reached a position in which the arms 30 are in a position to hold the blocking members out of engagement with the rail and wheel.

.A dash pot 44 is provided for retarding the reverse rotation of the shaft 31 while the blocking members are moving downwardly by gravity, the dash pot 44 being in the form of a cylinder connected at one end by a pivot 45 to the platform 32 and having a piston rod 46 pivotally connected to an arm 47 fixed to the shaft 31. The cylinder of the dash pot is provided with a by-pass 48 controlled by a valve 49 which may be set to determine the rate at which the blocking members are permitted to move to blocking position.

As shown in Fig. 8 of the drawing, the clutch coil 50 is connected across the motor circuit, and the coil and motor are controlled by a main switch 51. The limit switch 52 controlled by the arm 43 is in the motor circuit between the motor and coil, so that the opening of the motor circuit by the limit switch does not release the clutch. When the main switch 51 is closed the coil 50 is energized and the clutch 38 is engaged. If

when the switch 51 is closed when the blocking members are in operative position the motor will be operated until the arm 42 on the shaft 31 engages the arm 43 and opens the switch 52 which will stop the operation of the motor without releasing the clutch 38.

When it is desired to again seat the blocking members the switch 51 will be opened, de-energizing the coil 50 and releasing the clutch 38 which will permit the blocking members to move by gravity into wheel engaging position. The rotation of the shaft 31 during the setting of the blocking members causes the arm 42 to release the switch arm 43 permitting the switch 52 to close so that the motor 33 may be energized at any time to release the blocking members by closing the main switch 51.

Signaling devices are preferably provided in connection with each of the blocking members and each of these devices consists of a circuit 53 provided with a switch 54 in the path of movement of a lever 16 and so positioned with respect to the lever that it will be closed by the lever when the lever has reached a position in which the blocking members are held in inoperative position. When the switch 52 is closed a signal lamp 55 in the circuit will be lighted. These lamps will preferably be arranged in a group at the operators platform so as to show the operator which of the blocking members have been released and which are still held in engagement with the rail. By shifting the bridge in the proper direction the blocking members so held may be released and automatically shifted to inoperative position by the spring 26.

Having described my invention, I claim:

1. A safety sto for traveling structures movable along a trackway comprising a wheel blocking member engageable between a wheel and rail, a rail clamp associated with said blocking member, and means for applying a thrust to said member suflicient to shift the same out of wheel blocking position when the said member is free of the wheel and for maintaining said thrust if said member be held between the wheel and rail to automatically shift the member out of rail engaging position when the blocking member is released by a movement of the wheel.

2. The combination with a traveling structure adapted to be moved along a trackway, of a wheel blocking member adapted to be positioned between a wheel and a rail, a rail clamp associated with said blocking member, an actuating member on the frame, and means including a thrust transmitting sprin connecting said actuating member to the locking member for shifting the same out of wheel engaging position, said spring permitting full movement of the actuating member independently of the movement of the blocking member when the blocking member is held to the rail by a wheel and acting to shift the blocking member out of engaging position upon a movement of the structure releasing the blocking member from the wheel.

3. The combination with a traveling structure adapted to be moved along a trackway, of a wheel blocking member adapted to be positioned between a wheel and a rail, a rail clamp carried by said blocking member, a clamp actuating lever mounted on said block ing member, movable suspension members connected to the frame of said structure and to said lever, and means for actuating one of said suspension members to actuate said lever and to shift said blocking member.

4. The combination with a traveling structure adapted to be moved along a trackway, of a wheel blocking member having a connection with the frame of said structure and adapted to be shifted into and out of a position between a wheel and a rail, rail clamping means carried by said blocking member, an actuating member on the frame, means for moving said actuating member, means for actuating the clamping means including a lever connected to the blocking member, and a spring interposed between the actuatmg member and lever.

5. The combination with a traveling structure adapted to be moved along a trackway, of a wheel blocking member having a connection with the frame of said structure and adapted to be shifted into and out of a os1- tion between a wheel and a rail, a rail c amp associated with said blockinmember, and means for shifting said blocking member out of wheel engaging position including means acting when the blocking member is held against the rail by a wheel to maintain a predetermined thrust on the blockin member sufficient to shift the same out o blocking position when said blocking member is released by the wheel.

6. The combination with a traveling structure adapted, to be moved along a trackway, of a plurality of wheel blocking members, each engageable between a wheel and rail, levers on the frame connected to said blocking members, a rail clamp associated with each of said blocking members, an actuating member, means including a thrust transmitting spring for connecting each lever to the actuating member, means for movin said actuating members in a direction to s ift the blocking members out of wheel engaging position, said springs permitting full movement of the actuating member independently of the movement of the blocking members.

7. A safety stop for traveling structures adapted to travel on a trackway, comprising a wheel blocking member engageable between a wheel and rail, arail clamp carried by said blocking member, a counterweighted lever carried by the blocking member for operating the clamp, a lever carried by the frame of the structure, a link connecting said clamp operating lever to said lever on the frame, and a second link connecting the clamp operating lever to the frame.

8. A safety stop for traveling structures adapted to travel on a trackway comprising a wheel blocking member engageable between a wheel and rail, a rail clamp carried by said blocking member, a lever pivoted intermediate its ends on said blocking member and connected with the clamp to operate the same, a counterweight on the lever for setting the clamp, a lever on the frame of the structure for actuating the counterweighted lever and for shifting the blocking member, a link connecting the lever on the frame to the counterweighted end of the clamp operating lever, and a link connecting the opposite end of the clamp operating lever with the frame.

9. A safety stop for traveling structures adapted to travel on a trackway comprising a wheel blocking member adapted to rest upon a rail and having a'wedge portion at its forward end engageable between a wheel and rail, a rail clamp carried by said member adjacent the rear end thereof, and means for operating said rail clamp and for shifting the blocking member out of rail engaging positlon.

10. A safety stop for traveling structures adapted to travel on a trackway comprising a wheel blocking member adapted to rest upon a rail and having a wedge portion at its forward end engageable between a wheel and rail, a clamp comprising rail clamping jaws pivoted upon opposite sides of said member adjacent the rear ends thereof, said jaws having arms-extending upwardly above the pivots, a.lever extending lengthwise of the blocking member and .pivoted thereto forwardly of the clamping jaws, toggle links connecting said lever with the arms of the clamping jaws, a counterweight connected to said lever to move the same in a direction to set the clamp, and means connected to the clamp operating lever for releasing the clamp and shifting the blocking member out of wheel engaging position.

11. The combination with a traveling structure adapted to be moved along a trackway, of a wheel blocking member adapted to engage between a wheel and a rail, a lever pivoted on the frame of said structure and connected to said blocking member, a shaft on the frame having a crank arm, telescopically connected members connected one to the crank arm and the other to the lever, a spring interposed between said members, means for actuating said shaft in a direction to shift the blocking member out of wheel engaging position and for locking said shaft in a position to retain the blocking member in inoperative position, said sprin being adapted to permit movement of the s aft to its locked position independently of the blocking memmamas ber should the blocking member be held by the wheel against movement.

12. The combination with a traveling structure adapted to be moved along a trackway, of a plurality of wheel blockmg members each engageable between a wheel and rail, an actuating member on the frame, a yielding connection between said actuating member and each wheel blocking member, and means associated with the blockin members to indicate to the operator whet er or not all of the blocking members have been shifted by the actuating member.

In testimony whereof, I hereunto afix my signature.

ARTHUR F. CASE. 

